The present disclosure relates to vehicle drive devices including: a rotating electrical machine; a speed change mechanism disposed in a power transmission path connecting the rotating electrical machine and wheels; a fluid coupling that drivingly couples the rotating electrical machine to the speed change mechanism; and a case forming, as spaces that are independent of each other, a rotating electrical machine accommodating space accommodating the rotating electrical machine, a speed change mechanism accommodating space accommodating the speed change mechanism, and a fluid coupling accommodating space accommodating the fluid coupling.
Related art of such vehicle drive devices includes, e.g., a technique described in Japanese Patent Application Publication No. 2011-105195. In the description of this section, the names of relevant members in Japanese Patent Application Publication No. 2011-105195 are cited in parentheses “[ ].” In the configuration described in Japanese Patent Application Publication No. 2011-105195, an oil reservoir portion [oil reservoir portion 101] that stores oil to be supplied to a rotating electrical machine [electric motor 1] is formed in the lower part of the space in a case accommodating the rotating electrical machine. In this configuration, as described in paragraph [0045] and FIG. 2 of Japanese Patent Application Publication No. 2011-105195, oil in the oil reservoir portion is scooped up by rotation of a rotor [rotor 13] to cool the rotating electrical machine. In the configuration of Japanese Patent Application Publication No. 2011-105195, since oil scooped up by rotation of the motor is supplied to the rotating electrical machine, rotation resistance of the rotor tends to increase, which reduces energy efficiency of the device accordingly.
The vehicle drive devices typically include an oil reservoir portion that stores oil to be supplied to the speed change mechanism. Accordingly, in one possible configuration, oil in the oil reservoir portion is supplied to the rotating electrical machine. An example of such a configuration is a technique described in Japanese Patent Application Publication No. 2013-095389. In the configuration described in Japanese Patent Application Publication No. 2013-095389, oil in a first oil reservoir portion U1 communicating with a speed change mechanism accommodating space is supplied to a rotating electrical machine MG. The oil supplied to the rotating electrical machine MG is collected by a second oil reservoir portion U2 communicating with a rotating electrical machine accommodating space SG. The collected oil is supplied to the first oil reservoir portion U1 via a discharge oil passage AD. As shown in FIGS. 3, 5, etc. of Japanese Patent Application Publication No. 2013-095389, the discharge oil passage AD includes a first discharge oil passage AF extending in the horizontal direction from a first opening ADo that opens toward the first oil reservoir portion U1, and a second discharge oil passage AE extending in a downward direction (tilted downward at about 45 degrees) with respect to the horizontal direction from a second opening AEo that opens into the second oil reservoir portion U2 and communicating with the first discharge oil passage AF.